Pumping mechanism



1929- J. G. SCHOTTHOEFER 1,723,493

a v l t/ 5;

. g- 1929- J. G. SCHOTTHOEFER 1,723, 93

PUMPING MECHANISM Filed April 7, 1927 4 Sheets-Sheet 2 g- 1 1929- J. G. SCHOTTHOEFER 1,723,493

PUMPING MECHANI S M Filed April 7, 1927 4 Sheets-Sheet 3 it I Z1 59 J7 g @5616 as 1929- J. G. SCHOTTHOEFER 1,723,493

PUMPING MECHANI SM Filed April 7. 1927 4 SheetsSheet 4 Lia/67060;; JoJ O/b GAYC/LOW,

Patented Aug. 6, 1929 I JOSEPH G. SCHOTTHOEFER, F PEORIA, ILLINOIS.

PUMPING MECHANISM.

Application filed April 7,

A primary purpose of this invention is to provide a pumping mechanism of a nature such that it will deliver. liquid to a place of use for power, lubricating or other purposes,

under variable pressures with a most economical expenditure of the energy required in the operation of the pump.

In the accomplishment of this primary purpose the invention contemplates the pro vision of a pump comprising a plurality of related pumping units and a control means common to said pumping units and operative at the will of the operator to vary the quantity or volume of liquid discl'iarged by th pump. The invention further contemplates as important purposesthereof, the provision of means whereby the aforesaid primary purpose may be accomplished by simple and ellective means and more particularly by controlling means and liquid-forcing e1ements so correlated that many different volumes or quantities of liquids may be selectively delivered under pressure from the pump without complicating the construction of the pump or resorting to means of delicate or expensive construction.

To these several ends, the invention consists in certain novel combinations and correlation of elements substantially as hereinafter described and particularly set forth in the appended claims. v While I recognize that means illustrated in carrying is invention into practice are applicable in principle to pumps of various lrinds or types and while I contemplate the application of such means to pumps of any kind or type to which they are applicable, I have elected to illustrate and shall hereinafter describe the application of the invention to pumps of the rotary type, and especially to that kind of rotary pumps which include rotary impellers and appropriate intermeshing teeth forimparting rotary movement from one impeller or its shaft to another impeller or its shaft, without, however, intending thereby to restrict the invention in all of its respects to rotary pumps. Moreover, I am aware that details of the particular means illustrated in the drawings and ill 1927. fierial No. 181,695.

described in this specification may besubstant1a ll y varied without departing from the spirit of the invention as defined by appended claims. 'stood that the drawings illustrate and In short, I would have it underthe description sets forth preferred embodi lnents having many advantages in relation to the purposes underlying this invention.

In said drawings, wherein like characters of reference denote corresponding parts in all the figures Fig. 1 is a longitudinal section and emplifies the invention as applied to a rotary pump the peripheries of whose impellers provided with intermeshing teeth, this are fig

me also exemplifying a form of the invention in which the controlling means are ranged rearward of the impellers, the figure showing a controlling member and the mouth of a corresponding by-pass located. between the impellers and the corresponding check valve which controls the outlet port from corresponding chamber.

the

to cut oil the supply of the liquid to the chambers in which said impellers operate.

Fig. 3 1s a vertical section. on the llne 33 of either Fig. 1 or Fig. 2.

Fig. 4 is a vertical section on the line 4-4 of Fig, 5, (but with parts of the casing broken 05 and with certain parts omitted) this ure heingintended to illustrate a form of invention in which the rotary impellers connected for simultaneous movement in figthe are posite directions by intermeshing gears mounted upon the ends of the impeller shafts, instead of by intermeshing teeth formed on the peripheries of the impellers themselves.

Fig. 5 is a vertical section on the line 5-5 of Fig. 4.

Fig. 6 (Sheet 2) is a horizontal section on the line 66 of Fig. 1. I

Fig. 7 is an end elevation of the construction shown in Fig. 1. Fig. 8 is a side elevation of the emb ment illustrated in Fig. 1.

cw or Fig. 9 is a detail view of one of the inside plates which separate pumping units from each other.

Fig. 10 is a detail view of the indicator and the cams forming a part of the controlling means applicable to the form of the invention in which the supply to the pump is controlled at a place in advance of the rotors. (See Fig. 2.)

Fig. 11 is a detail view of the cams applicable to the form of the invention in which the controlling means is between the i n pellers and the check valve. (See Fig. 1.)

The pump forming the subject of this invention essentially includes a plurality of separate pumping units each having an inlet port, an outlet ort and a liquid-forcing means operating between said ports. These units may be of any suitable construction appropriate to the purpose to which the pump is to be applied. While there may be any suitable number of units, more than one,

. three of said units have been illustrated since this number will be appropriate in many instances. These units include chambers desi ated respectively A, A and A The c ambers are preferably arranged in a casing constructed of a front member A a rear member A, and a suitable number of internal plates A". These members and plates are rigidly secured togetheras by bolts 15 and nuts 16in proper relations to provide the said chambers A, A, and A. In the embodiment of the invention in which provision is made for by-passing the part of the liquid delivered to the pump in excess of that to be delivered at the place of use, the members A, A and plates A are, as shown best in Figs. 1 and 6, also formed to provide an inlet chan' nel B, an outlet channel B, and a bypass channel B and also ports 1) connecting the inlet channel B with the chambers, respectively, ports 6' connecting the respective chambers with the outlet channel B and ber. The arrangement shown in Fig. 1 may be preferred particularly when oil is the liquid pumped and the liquid-forcing means are of a kind requiring lubrication, since the said arrangement will .assure continuous lubrication thereof while the pump is in operation.

The illustrated liquid-forcing means is composed of rotary impellers C and C operaposite directions through appropriate con- 4 nections. As shown in Figs. 1 and 2, their peripheries may be formed with teeth 20 of which those of one impeller inter-mesh with those of the other impeller, the spaces between the bases of the teeth providing pockets 21 for the liquid. In another form, illustrated in Figs. 4 and 5, the gears, marked 20 and 20", instead of being formed on the peripheral surfaces of the impellers, marked C and C", are mounted on the impeller shafts, and the peripheral surfaces of the impellers instead of having intermeshing teeth for transmitting rotary movement from one to another are each provided with two teeth 0, and with two openings 0', arranged as shown. The spaces between the teeth 0 in this form provide elongated pockets for the liquid pumped. In both forms the pockets are defined by the sides of the teeth, the peripheral surfaces of the impellers and those parts of the walls of the chambers with which the outer ends of the teeth contact in the operation of the impellers. I It may be here mentioned that while the several passages and ports for the flow of the liquid within the pump have not been shown in Figs. 4 and 5, yet in the practical embodiment of this form, these passages and ports will be included, the casing being preferably of substantially the construction shown in relation to the form in which the impellers are geared together through the medium of intermeshing teeth formed on theirperipheries, except that when the ears are mounted on the shafts the casing w ll preferably include, as shown, provision for the enclosure of said ears.

It will be understood that there is a pair of impeller sections in each chamber A, A and A. Because of the resultant simplicity of construction, it is preferred that each impeller, instead of being composed of independently rotative sections mounted in the respective chambers, be of a unitary construction; that is that its sections and shafts be substantially integral. This preferred construction, therefore, has been illustrated. Upon reference to Fig. 3 it will be noticed that each impeller C, C has its ends formed to'provide shafts 24 which extend through openings formed in the side members A and A of the casing. Adjacent these shafts, each impeller lias shoulders 25 which bear against the inner surfaces of said casing members surrounding the shaft openings, and intermediate its said shoulders each impeller has'recesses 26 to receive the portions of the divig sion' lates A bounding the-openings 27 lltl wardly projectin means (see 7 ig. 9) formed in each divisioh plate,

these openings being provided to permit the,

unitar shafts and impeller sections to extend theret rough. One of the shafts 24 is extended outward for the attachment thereto of a prime mover, not shown, of any suitable kind. A stufiin box includin members 28 and 28 is pre erabl mounte on this extended shaft end. T e end members A and A are provided with flanges 29 which are concentric with the shafts 24 and are spaced therefrom, and friction-reducing bearings, as rollers 30, are interposed between said shafts and flanges. A casing plate A closes the outer side of the member A and a casing plate A, together with the member 280i the stufling box, closes the outer side of the memher A.

The impellers G and U andtheir shafts similarl are preferably of unitary construction an said impellers haveshoulders and recesses as described in relation to the other term. Each internal division plate A in this embodiment also islilre the corresponding plates of the other embodiment of the invention, but there is one additional plate and the shoulders of one end of the impellers bear against this additional plate. The side member, marked A, (see Fig. 5) correspond ing to the member A in the other form, is spaced from this additional division plate to provide between them a chamber to receive the gears 20 and 20*. This end plate has butflanges 29 formin rings concentric with the shafts 24 to provide for friction-reducing bearings, as rollers (30) similar to those marked 30 in the other form, and one of these rings is closed at its outer end by the member 28 of a st-ufling box while the other rings are closed at their outer ends by plates 30*. Thus in this particular exemplification, the gears as Well as the impellers are encased. The enclosure of the gears is, however, not essential.

Each of the division plates A is divided, as along the line a, Fig. 9, for convenience in assemblin the parts when the impellers and their shaiis are of integral formation.

For reasons which will hereinafter be egrplained, the chambers A A, and A are of relatively diiferent capacit-ies and the sections of the impellers within said chambers are of correspondingly different sizes; that is, longitudinally of the'impellers, the sections in the chamber A are the shortest, the sections in the chamber A are the longest and the sections in the chamber A are of a length intermediate the others.

Individuall operable check valves D are operatively re ated to each outlet port b and to the channel B common to said ports and individually operative control valves E arranged in advance of said check valves. In practice, the discharge end of the channel B is connected to a to which the pum e for use, as in app ying ower to move an object for -example. The -pass channel 13 is preierably connected with the source of supply of the liquid, and in the embodiment shown in Figs-1 and 6 the control valves E are operatively related to the by-pass ports 1) connecting the outlet ports I) with the by ipass channels B he illustrated check valves D are provided with sprin s whose tension will hold them severally c osed against their seats exce t when overcome by the pressure of the liquid being pumped through the corresponding outlet ports or channels 6. The liquid will exert suc pressure in the operation of that embodis ment of the invention em loying a byass, when the corresponding Ey-pass port, 2 is closed. When, however, any one or more of such by pass ports h is o iencd by its valve E, the pressure of the liquid, if any pressure is exerted against the corresponding check valve or valves D, will not cause said check valves to open, even when the bypass orts are between the impellers and the outlet 0 annel B, since the liquid will then be discharged into the by-pass channel B from which it will be returned to its source, or be otherwise disposed of.

In that embodiment of the invention in i e leadin to the place. dhid is tea conducted which provision is made for the cutting oil of the supply of liquid to any of the chambers through the med1um of valves, as E, controlling the inlet channels, the check valves D,

of course, will be opened only when the cor responding control valves E are open, since at this time only will the pressure of the liquid against the check valves be suflicient to open them.

In short, in the one illustrated embodiment, the closing of any control valve causes the flow of liquid to the corresponding chamber to be cut off, and in the other illustrated enibodiment the opening of any one of the control valves causes the flowlo'f liquid from the corresponding chamber tobe cut off, and in either embodiment thiscutting oil of the flow of liquid, being in advance of the check valves, will correspondingly cut down the su ply to the outlet channel B.

t will be apparent that the springs d be- 7 come operative to 'close the corresponding check valves when the-pressure of the li uid in the corresponding chamber drops be ow that predetermined for the opening of said valves, and also that the closing of any check valve cutsoff from-the corresponding chamher an back pressure created by the resistance o the load to the pressure exerted thereagainst by liquid-being pumped from one or more of the chambers whose by-pass ports are closed and whose check valves are open. Hence, it will be noted that the correlation of impellers, check valves, inlet and outlet ports and channels, and also the by-pass when used,

is such that the work of the impellers is confined to the pumping of only the quantity or volume of liquid re uired for the work to be performed by said iquid at the correspondmg moment and that it performs its work without any interference due to back pressure even when it is delivering the liquid from one of the chambers only and that the one of smallest capacity.

Thus, it will be apparent that the power applied to operate the pumps will vary in ac ordance with the variations in the quantity or volume of liquid delivered for use, without neuessitating an variation in the speed of the impellers. n this relation, it should be particularly noticed that the by-passing of that part of the liquid delivered to the pump which is in excess of that to be delivered at the place of use occurs at a place or places at which the liquid is not under pressure, whereas it has heretofore been the practice, with.

those pumps employed in systems in which variable conditions as to pressure, resistance etc. have been met by by-passing the part of the liquid in excess of that required, to so bypass the liquid at a place or places in the system at which the liquid is under pressure and since in such systems the pump is operating at alltimes at the same speed, it accordingly 4 has been called upon to pump the same quantity or volume of liquid and requires the same amount of energ to operate it under all conditions of uset lat is, whether all or whether only apart of the volume or quantity of liquid pumped is actually delivered at the place of use. In the instant invention, however, the energy supplied by the prime mover is lessened in accordance with the number of pumping units whose by-passes are open and the saving of power in the operation of the pump, therefore, will be apparent. -This presupposes that the resistance to the pressure of the liquid remains the same. If, however, the pump is applied to a work which the resistance to the pressure of the liquid pumped is variable, the power applied to the pump by the prime mover may remain constant, the speed of rotation of the impellers similarly may remain constant, while the quantity or volume of liquid delivered may vary in accordance with the varying resist ances, it being apparent that when the resistance is increased and the volume of liquid correspondingly reduced, the pressure of the liquid will be increased to meet the increased resistance, if the power of the prime mover applied to the pump remains the same.

\Vhile reference has herein been made to a pump whose liquid-forcin means, herein exemplified by rotary impel 'ers, have been assumed to operate at a constant speed under all conditions, and while the prime mover has also been referred to as being one operating to deliver variable power to the pumping means, it is ap arent that the mechanism may be employe with an a p'ropriate prime inover and connections, un er conditions in which it is advisable to,vary the speed of the pumping means. By thus varying the speed of the pum ing means, the capacity of each section of t 10 pump, and of the pum as a whole, may be correspondingly varie and this variation will result in a corresponding variation in the pressure ap lied by the pum since it corres ondingy varies the spee of flow of the iquid and hence the volume delivered within, a given time.

This invention contemplates as one of its most important features the provision of a control means operatively related to the pumping means and their chambers, and to the ports and channels provided for the flow of the liquid, and which control means is op- ,erativeto effect a selective control of the flow of the li uid, the said control means being further 0 such nature-that it will be capable of cooperating with the pumping means, chambers, ports and channels to bring about a change in the volume or quantity of liquid delivered by the pump, at the will of the operative, without necessitating any chan e in the speed of operation of this ump. is control means operates the va ves E and in the illustrated embodiments of the invention is additionally characterized in that it is operative to control said valves both individually and in different combinations thereof. effecting correspondin' changes in the delivering of the liquid. fieference has hereinbefore been made to the fact that the chambers A, A, and A? may be of relatively different capac ities and that this is true also of the liquidforcing means therein. Therefore, it will be apparent that when the liquid delivered is that which passes through the smallest chamber (A) only, the quantity or volume thereof will be less than that which will be delivered when it passes through the second chamber (A and still less than that which passes through the next chamber. The difference in-the capacities of the chambers A, A and A accordingly contributes to the production of changes of successively increasing or successively decreasing 'nature. Moreover, by providing for the control of the liquid with respect to different combinations of the chambers, the number of the changes which may be effected is correspondingly increased. It will be noted that the changes thus far referred to are accomplishable without any change in the speed of the liquid-forcing means and without any difference in the extent of the opening of a control valve. A wider range of changes, however, may be effected without any change in the construction of the pump, by operating its liquid- -meansers and connections to the ump. In a pump l 7 having such provision, t e volume of the changing the speed of the liquid-forcing means; Thus concluding this reliminary summary of the results obtaina 1e from a correlation of parts including, a control meansof the nature contemplated'by me, I will nowdescribe embodimentsof the control means suitable for the purposes, the said embodiments being alike in principle but dill'ering in details to ada t them to the forms of the invention exemplified by Fig. 1 and Fig. 2, respectively.

As already stated, this meansmav be conveniently applied to control the valves E. These valves, therefore, are of a nature suitable for control by said means, being here shown as having members E extending to places where they, respectively, may be operated upon by cams F, G and H, (Fig. 10) or F, G nd H, (Fig. 11), which cams operate to move the valves E in op osition to coiled springs E. In each of t ese exemplifications, the springs tend to open the valves andthe cams to close them.

In each, the cams (F, G and H inthe one form and F, G and H in the other form) are mounted upon a common shaft, which being identical in both embodiments is marked I throughout the drawings. In each en'ibodiment, moreover, the cams have high and low parts so correlated that the control of the valves E individually and in predetermined combinations hereinbeiore referred to may be brought about at the will of the operative, but in the embodiment illustrated in Figs; 2 and 7, the high parts of the cams (Fig. 1d) are arranged'to close the valves E corre' sponding to chambers which are to be out out of operation by said closing, while in the embodiment in which the valves E are arranged to control by-pass ports between the chambers and check valves, the cams (Fig. 11) are arranged to close the valves E corresponding to chambers which are to be and which become operative by said closing.

Thus referring first to the embodiment in which the valves E are arranged in advance of the rotors, and particularly to Figs. 2, 7 and 10, itwill be noticed that the cam F has peripheral openings 30, 31 and 32 and high parts 36, 39 and ll; the cam G has peripheral openings 33 and high parts 37 and 40; and

lit)

till

the cam H has a peripheral opening 35 and a high part 38. The cam F is arranged to operate the valve E corresponding to the smallest chamber (A); the cam G is arranged to operate the valve E corresponding to the intermediate chamber (A and the cam H is arranged to operate the valve E cor responding to the largest chamber (A A dial or indicating plate J is also mounted upon the,shaft I. The late J and cams are keyed upon the shaft 1 in relative position such that when all of the valves E are closed the dial will indicate the, same by the position of ts zero mark and the high arts 36, 37 and 38 of the respective cams will be in contact with the ends of the valve members vE' respectively. If now, it is desired to utilize the flow of liquid from chamber A allone, the

shaft I is turned by any appropriate means until the indicating mark 1 on the dial J will be in the position which indicates that the shaft I has been turned sufiicientl to carrythe high part 36 of cam F'out o engagement with and the opening into registration with its corresponding member E. The spring which operates the valve E corre sponding to chamber A then becomes efiective to 0 en said valve. The high parts 37 and 38 o the cams G and H at this time remam in engagement with the valve members corresponding to chambers A and A since the movement of the cams has not been sufficient to disengage them from said members. A further movement of the shaft 1, to the position indicated bymark 2 on the dial, will carry thehigh part 39 of cam F into engagement with the corresponding valve member, thus closing the valve E corresponding to chamber A, and at the same time will carry the high part 37 of cam Gout of engagement with the valve member E eorresponding to chamber A and the opening 33 of said cam into registration with said valve member, whereupon the valve E corresponding to said chamber A will be opened. A stillfurther movement of the shaft I, to the position indicated by the mark 3 on the dial, will disenga e the hi h part 38 of cam H from the mem er E50? the valve corresponding to chamber A and will place the recess or low part of said cam into registration with said valve member, whereupon the correspondin valve E will be opened by its spring. Th has brought the high part of cam G into engagement with the member E of the valve corresponding to chamber A, so that said valve is closed thereby, but has not been sufficient to disengage the high part of 39 of cam F from the corresponding valve member and hence the valve E corresponding to chamber A remains closed. Thus it will be seen that the flow of liquid from the chambers to the place at which the'liquid is to be used may be so controlled that the liquid delivered at said place, may be that from any one of the chambers, and since these chambers vary in their capacities the volume of the liquid delivered at a given time will be correspondingly varied. It may be here mentioned that is movement of the shaft the relative variations in the capacities of the I from chamber A'in a given time wi 1 be retical spectivel one and one-half and twice that delivere from chamber A. These are prac reportions which, however, may be varied if referred. If now it is desired to deliver a larger volume than is obtainable from chamber A alone, a still further movement of shaft I to the position indicated by dial number 4 will carry the high part 39 of cam F out of engagement with t e member E of the valve E corresponding to chamber A and the recess or, low part 31 of said cam into registration with said valve member but this movement will not be sufficient to disengage the high art 40 of cam G from the corresponding va ve member, or to re-engage the high part 38 of cam H with its corresponding valve member. Hence, the valves corresponding to chambers A and A will be opened while the valve corresponding to chamber A will remain closed. The next step in the increasing of the volume delivered at the place of use will be the closing of the valvecorres onding to chamber A and the opening of tlie valve corresponding to chamher A, without, however, closing the valve corresponding to chamber A This is accomplished by turnin the shaft I until the indicating mark 5 is in indicating position. This movement carries the high part 41 of cam F into engagement with the member of the valve corresponding to chamber A, thus closing said valve, and at the same time par ries the low part 34 of cam G into registration with the member of the valve E corresponding to chamber A, thus permitting the spring E of the latter valve to open the same; but since this movement is insufficient to bring the high part 38 of cam H into engagement with the member E of the valve E corresponding to chamber A, the latter valve remains open. The last step in the control of the volume delivered at the place of use, in this embodiment of the invention, is the turning of the shaft to the position in which the dial indicator 6 is in indicating position. This movement of the shaft causes the recess or lower part 32 of cam Fto register with the member D of the valve E corresponding to chamber A without engaging high parts of the other cams with their re spective valve members. Hence, the volume of the li uid now delivered will be the aggregate of t at flowing from all three chambers. A further turn of the shaft I to the position at which the zero mark on the dial is in indicating position will cause the high parts of all the cams to engage their respective valve members E thus closing all valves E and cutting off the flow of liquid entirely.

- Referring now to the embodiment in which the valves E are arranged between the rotors and the check valves D are control by -pass' ports b, and particularly to Figs. 1, 8 and 11, it will be noticed that the high parts of in substantially the same position as the means the cams (marked F, G and H in this embodiment) are dis osed. in substantially the same ition as t e low arts of the corres'pondingcams' F, G and 1, and that this is true also with relation to the low parts of said cams F, G and H, the said low parts being hi h parts of the cams F, G and HL In the o x iition, therefore, of this particular em diment, when the indicator, (which being identical in both forms is marked J throughout the drawings) is turned to the zero position, low parts 30, 35and 39 of the cams F, G and H will be presented to the res )ective valves E which valves at this time will be held in open position by their springs E, thereby causing allliquid from the several chambers to be by-passed. When the shaft is turned to the position indicated by l on the indicator J, the corresponding valve E will be closed by the high part 31 of cam F thereby ren-' dering chamber A efi'ective; when the shaft is turned further, as to the position indicated by 2 on the indicator J, the high part 31' of cam F will be disengaged from the corresponding valve E which valve will thereupon be opened and the high part 36 of cam G will be engaged with the valve E controlled by said cam, the said valve being thereby closed, the opening of the valve controlled by cam F thus rendering chamber A ineffective and chamber A effective; a still further turning of the shaft I, to the position indicated b 3 on the indicator J will disengage the hig 1 part 36 of cam G from its valve E and will engage the high part 40 of the cam H with the valve E controlling chamber A, At this time the low part-32 of cam F remains presented toward its valve Eand hence said valve, which controls the by-pass port corresponding to chamber A, remains in open position. Accordingly, it will be seen that when the shaft I has been turned to the position indicated by 3 in indicator J, chambers A and A will be non-effective since the corresponding b -pass ports b will be open and hence liqui pumped from said chambers will flow into the by-pass B instead of into the conduit or channel B, while chamber A will be effective, since the corresponding by-pass port I) will be closed. Turning of shaft I to the position indicated by 4 on indicator J will engage the high part 33 of cam F with the corresponding valve E without disengaing the low part. 37 of cam G from its valve and without disengaging the high-part 40 of cam H from its valve. It follows, therefore, that in this position. of its shaft and cams, the

.valves E controlling the by-pass ports I) corresponding to chambers A and A will be closed while the valve E controlling the port 6 corresponding to chamber A will remain open; hence chambers A and A will be nonefiective. A still further rotation of the shaft till to the position indicated by 5'on the indi-' cator J will disengage the high part 33 of cam F from the corresponding valve E and present the low part 34: of said cum to said valve, and at the same time will engage the high part 38 of cam G with the corresponding valve but will not disengage the high part 40? of cam H from its corresponding valve. Hence, in this position of the parts the valve controlling the bypass port corresponding to chamber A will be open and'said chamber will be ineffective to supply liquid to the conduit or channel B, while the valves controlling the bypass ports corresponding to chambers A and A will be closed. and said chambers thereby will be efi'ective to supply liquidto said conduit or channel. A still further rotation of the shaft, to the position indicated by 6 on the'indicator J will engage the high part "30 of cam F with its corresponding valve hi without disengaging the high parts 38" and d oil the cams Gr and H from their respective valves it the result being that all chambers A, A and fl? will be eilective to supply liquid under pressure to the channel or conduit B since all by-pass ports are closed by their respective valves. Finally, the neat movement given the shaft l, to the position indicated by 0 in the indicator J, diseugages the high parts of all cams from the valves respectively and'presents the low parts and 89' of said cams to the respective valves, whereupon the springs E of the valves become ell'ective on the valves to open all the bypass ports, thereby rendering all chambers non-eficctive to supply liquid to the conduit or channel B.

lit will be understood that the type or kind cl pump--that is, whether it be of rotary or other nature-the number and the relative capacities oi? the pumping units, the number of the selectible combinations of the pumping units and, in short, the details herein illustrated are matters of choice and may be sub stantially varied. within the scope of appended claims.

Having thus described the invention and set forth in detail what I regard to be the most practicable embodiment, what I claim as my invention and desire to secure by Letters Patent, is

1. it pumping mechanism comprising a plurality of pumping units, eachhaving a check valve and each also having a control valve arranged in advance of its check valve, and a control means common to said control valves and including a plurality of members opcratively related to said valves respectively and operative to control the same selectively.

2. A pumping mechamsm compris ng a plurality of pumping units each having a control valve and each also having a check valve arranged rearward of the control valve, a liquid supply channel having ports for the inlet of the liquid is said units, ni

3. A pump comprising a casing having a plurality of chambers and provided with an inlet channel and an outlet channel and with ports through which each channel. has separate comniunica'tion with the corresponding chamber,the casing also having bypass ports operatively related to the chambers, respectively; valves to open and close the by-pass ports, respectively; and a means common. to said valves and including members respectively operative with relation to the valves to cause the same to be opened and closed selcc tively.

d. A pump comprising a plurality of pumping units and provided with an inletchannel and an outlet channel and with ports through which each channel has separate communication with the units, the pump also having by-pass ports in advance oi. the out let channel; check valves operativcly relat ed to the respective units and to the outlet channel; by-pass valves for the respective bypass ports; and a means common. to the bypass valves and including members respec tively operative with relation to said valves and operative to control the same selectively.

5. A. pump comprising a casing having a plurality of chambers and provided with. an inlet channel and an outlet channel and with ports through which each channel has sep arate communication. with the chambers, the casing also having lay-pass ports in advance of the outlet channel, check valves operatively related to the respective chambers and controlling communication thereof with the out-- let channel, by-pass valves for the respec'- tive bypass ports, and a means common to the bypass Valves and including members respectively operative with relation to said. valves and operative to control the same selectively. I i

6. A pump comprising a plurality of chambers, rotary impellers therein, check valves at the delivery sides of the chambers and a plurality of control valves inoperative relation with the chambers and controlling the flow of liquid in. advance of the check valves, and a control means common to said control valves and including members operatively rc-' lated to the valves respectively.

7. A pump comprising a casing having a member therein formed of sections which conjointly form a Wall dividing the casing into a plurality of chambers, and a pair of rotary impellers each having a substantially integral .body part and shaft, with its body part e'xtendingthr'oug h the division member to prowhich are seated in said grooves of the im-- vide working sections thereof in both chamber are seated.

. 8; A pum comprising a casing, a pair of rotary impeilers mounted in the casing and eachhaving a body part provided with a peripheral groove separating it into separate working sections, and means co-operatlng with said sections to divide the casing into a plurality of separate pumping 'imits, in parallel, including separate chambers which receive corresponding sections of both impellers, said casing-dividing means formed of sections having openings the boundaries of pellcrs, respectively. J

9. A pump comprising a casing, a pair of rotar impellers mounted in the casing and each laving a body part provided with a peripheral groove, and division plates todivide the casing into a plurality of chambers of dif fcrent capacities each of which chambers receives corresponding sections of both impellers, each of said plates formed of sections having openings the boundaries'of which are seated in corresponding parts of the grooves of the impellers, respectively.

' 1 0. A pump comprising a plurality of pumping units, a plurality of control valves in operative relation with the units, respectively, a control means for the valves including members operatively related to the respec tive valves, and a means having elements which partake of movement imparted to said members and which respectively indicate the positions of said members. with relation to the valves.

11. A pumpcomprising a plurality of pumping units, a plurality of control valves in operative relation with the units, respectively, a control means for the valves including cams whose high and low,- parts are correlated with each other and with the valves to control the valves selectively, and a means movable with said cams and having elements related to the high and low parts thereof to indicate the positions of said parts with relation to the valves.

12. A pump comprising a plurality of pumping units, a plurality of control,valves in operative relation with the units, respectively, a control means for the valves including a rotative shaft and aims mounted on the shaft and whose high and low parts are correlated with each other and with the valves to control the valves selectively and a dial also'mounted on said shaft and movable therewith and with said cams and having elements related to the high and low parts of said came to indicate the positions of said parts with relation to'the respective valves. 13. A rotary pump comprising a lurality of pumping units each having an in ct port,

an outlet port and rotary pumping means opcrating between said ports, each unit also having a check valve controllin the outlet port and a control valve arrange in advance of the check valve and operative to control the pressure exerted by the pumping means 7 against said check valve, in combination with a means to open the control valves, said means including members settable by the operation of said means to different selecting positlons with respect to each other and to plurality of pumping units each havlng a tensioned check valve at the delivery side thereof and a tensioned control valve in advance of the corresponding check valve and a control means common to said control valves and including a plurality of members operatively related to said control valves respectively and co-operating with the tensioning means of the control valves to operate the' latter se- 7 lectively.

15. A pumping mechanism comprising a plurality of pumping units, each having a tensioned check valve at itsdelivery side and each also having a control valve in advance of the check valve, tensioning springs to move the respective control valves in one'direction,

a rotative shaft having cams, respectively, to operate the control valves in opposition to the springs of the latter, the cams having high and low parts correlated with each other and with the control valves to operate the latter selectively in accordance with the positions to which they have been set by rotative movement imparted to the shaft, and a member also mounted on said shaft and havingelements correlated withthe high and low parts of the cams to indicate the positions of the latter with relation to the control valves.

16. A rotary pump including a casing having a. partition wall dividing it into a pluralityof separate chamb ers, said chambers having separate supply ports and se )arate discharge ports, selectively controlla le control valves for said chambers, respectively, and rotary impellers having co-acting impeller sections arranged in each of saidchambers, 1

and co-operating with said wall, ports and valves to provide a plurality of rotary pumping units, in parallel.

In testimony whereof I aflix my signature.

JOSEPH G. SCHOTTHOEFER. 

